This invention lies in the field of liquid control valves. More particularly, it concerns flow valves which are used to control the flow of liquid from a conduit into a receptacle, such as, for example a stock tank for providing drinking water for cattle, to maintain a selected level of liquid in the tank. U.S. Pat. No. 4,352,371 is an example of a number of patents which disclose such float-controlled valves. In this invention, a pressure or level sensitive mechanism other than a float is used to control the closing and opening of the second small opening.
While the float operated mechanism to close and open the second small orifice works beautifully under normal conditions, in the wintertime, where the tanks are outdoors and are subject to freezing temperatures, such floats are normally subject to damage by the ice cover and the breaking of the ice cover of the water in the tank. This invention is directed to providing a means other than a float operated mechanism to control the flow of liquid from the conduit, and particularly to a substantially completely submerged mechanism.